clk: fixed-factor: add optional accuracy support

Fixed factor clock reports the parent clock accuracy. Add flags and acc
fields to `struct clk_fixed_factor` to support setting a fixed
accuracy. The default if no flag is set is not changed: use the parent
clock accuracy.

Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
Link: https://lore.kernel.org/r/20240221-mbly-clk-v7-1-31d4ce3630c3@bootlin.com


Signed-off-by: Stephen Boyd <sboyd@kernel.org>